The present invention relates to artificial kidneys and particularly to a peritoneal artificial kidney for removing toxic substances from the peritoneal cavity.
Artificial kidneys based on peritoneal dialysis are increasingly being used as a treatment for patients suffering from renal insufficiency. In peritoneal dialysis, a sterile dialysis solution is infused into the peritoneal cavity, and after absorbing waste metabolites, it is discarded, the process being repeated. This dialysis method has been used mainly with patients where hemodialysis is not feasible for various physiological reasons. However, this technique is increasingly becoming more attractive for general application for a number of reasons, including its great simplicity, its avoidance of involving blood directly, and its probably better removal of toxic metabolites of molecular weight of 300-1500 ("middle molecules"). These advantages, particularly the fact that blood vessels are not involved, make this method highly attractive for home dialysis since, as distinguished from hemodialysis, there is no life danger in case of a mechanical malfunction such as a leaking tube or air bubbles.
Machines for peritoneal dialysis commercially available today are basically of two types. One is simply a timer operating in conjunction with a large reservoir of sterile dialysing solution. The time for inflow, dwell and outflow can be predetermined as desired. A more sophisticated machine serves both as a timer and as an automatic mixing machine. The dialysing solution is prepared by the machine using tap water purified by reverse osmosis and a concentrate of salts and sugar. In the latter machine, a heat sterilisation step is required by health authorities. This makes it more complicated and expensive. Also, the dialysis using such a machine (as all conventional peritoneal dialysis) is relatively inefficient, giving urea clearances of 20-25 ml/min.